Graphene wet spinning solution, its preparation method, and its application in graphene fibers

Abstract

This invention belongs to the field of graphene fiber technology, and discloses a graphene wet spinning solution, its preparation method, and its application in graphene fibers. A first dispersion containing graphene oxide as the dispersed phase is mixed with a second dispersion containing a two-dimensional conjugated material with a macroporous structure. First, the two-dimensional conjugated material with a macroporous structure is controlled to form a stable interaction with the graphene oxide sheet. Then, the two-dimensional conjugated material with a macroporous structure is controlled to precipitate and grow on the surface of the graphene oxide sheet. Unreacted raw materials are then removed to obtain the graphene wet spinning solution. The graphene wet spinning solution is used to produce graphene oxide fibers (wherein the sizing agent contains a two-dimensional conjugated material with a macroporous structure) using wet spinning. These fibers are then subjected to reduction treatment to obtain graphene fibers. The graphene fibers obtained by this invention have high bending toughness and good electrical and thermal conductivity, and can meet weaving requirements.

Description

Technical Field

[0001] This invention belongs to the field of graphene fiber technology, and relates to a graphene wet spinning solution, its preparation method, and its application in graphene fibers. Background Technology

[0002] Graphene fibers have attracted widespread attention due to their excellent electrical and thermal conductivity and high specific strength. However, a series of problems remain in the process of transforming them into practical engineering materials. While graphene fibers possess advantages such as high mechanical strength and good electrical conductivity, they are also quite brittle, with low flexibility, making them prone to brittle fracture during weaving. Furthermore, the surface of graphene fibers often contains numerous structural defects; the surface is rough and the pores are not completely filled. This typically increases friction between fibers, further amplifying the structural defects. This not only makes continuous weaving difficult but also affects the electrical and thermal conductivity of the graphene fibers themselves due to the increased defect level.

[0003] To address the aforementioned issues, existing technologies, such as patent application CN119553392A, disclose a method for preparing continuous graphene nanofiber bundles. This method involves first preparing graphene oxide fibers and then reducing them to obtain graphene fibers. However, in the process of preparing graphene oxide fibers, a polymer is used as a plasticizing phase. While this can improve the toughness of the graphene fibers, it can also affect their performance.

[0004] Patent application CN119980683A discloses a graphene fiber thermally conductive and high-temperature resistant composite material, its preparation method, and its application. This method involves embedding graphene fibers in metal powder and then molding it after firing at temperatures above 2000℃. However, the composite material described in this patent requires ultra-high temperature treatment, and its surface is ultimately covered by metal carbides. Metal carbides possess high strength and hardness, which can exacerbate wear on the needle tips during weaving. Furthermore, while it primarily improves thermal conductivity, it does not mention improvements to other properties.

[0005] Patent CN119900120B discloses a wear-resistant nanofiber-reinforced graphene fiber, its preparation method, and its application. The method involves blending graphene powder and inorganic nanofibers to form a wet spinning solution, followed by wet spinning to obtain graphene fibers. The resulting graphene fibers utilize a porous network structure formed by the inorganic nanofibers to buffer stress, achieving wear resistance while maintaining a certain degree of weavability. However, the introduction of inorganic nanofibers not only weakens the electrical and thermal conductivity of the graphene fibers themselves but also leads to severe wear on the knitting machine needles caused by the inorganic nanopowder during weaving.

[0006] Patent application CN120247578A discloses a unidirectional graphene fiber carbon / carbon composite material, its preparation method, and its application. First, graphene fibers are impregnated in a phenolic resin solution, then subjected to high-temperature carbonization to remove organic components. A layer of pyrolytic carbon is then deposited on the surface using vapor deposition. This process is repeated several times to obtain a sandwich structure consisting of a graphene layer, a resin-carbon layer, and a pyrolytic carbon layer. The aim is to obtain a unidirectional composite material through different layering methods. However, the structures of both the resin-carbon and pyrolytic carbon contain numerous defects that do not positively improve the electrical and thermal conductivity of the graphene fibers or enhance their toughness.

[0007] Patent application CN120059233A discloses a method for preparing polypyrrole graphene oxide cellulose hydrogel and its application. The hydrogel material is prepared by combining graphene oxide and a cellulose crosslinking agent. However, it is only used as a hydrogel composite material with good photothermal conversion effects and cannot form graphene fiber materials.

[0008] Due to the aforementioned problems with existing graphene fibers, the resulting fabrics cannot meet the needs of various fields when woven from them. For example, patent application CN119212135A discloses an integrated electrothermal element and electrode material based on a fiber-woven structure, an electrothermal composite material, and its preparation method. This method involves first weaving carbon fibers or glass fibers into a 2D fabric, and then growing graphene in situ on the 2D fabric to obtain a fabric with a graphene layer. However, the application of this composite material is limited by the shape of the application area, and twisting or bending can cause the surface graphene layer to crack. Therefore, it often requires an outer resin coating.

[0009] Furthermore, in order to obtain functional fabrics made of graphene fiber materials, the patent with authorization announcement number CN119408275B and the patent application with application announcement number CN119840259A respectively obtain functional yarns by blending graphene fibers with nylon or by covering graphene fibers with polyester yarns, and then weaving them into shapes. The graphene functional yarns or fabrics obtained in this way are only suitable for ordinary civilian functional yarns and cannot meet the application requirements in fields with high electrical conductivity and high thermal conductivity.

[0010] Therefore, it is necessary to propose a graphene fiber that can solve the above problems. Summary of the Invention

[0011] The purpose of this invention is to solve the problems existing in the prior art, provide a graphene wet spinning solution and its preparation method, and further, use the graphene wet spinning solution to prepare graphene fibers and fabrics.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] A method for preparing a graphene wet spinning solution involves mixing a first dispersion in which graphene oxide is the dispersed phase with a second dispersion in which a two-dimensional conjugated material with a macroporous structure is the dispersed phase. First, the two-dimensional conjugated material with a macroporous structure is controlled to form a stable interaction with the graphene oxide sheet. Then, the two-dimensional conjugated material with a macroporous structure is controlled to precipitate and grow on the surface of the graphene oxide sheet. Finally, unreacted raw materials are removed to obtain the graphene wet spinning solution.

[0014] Two-dimensional conjugated materials with macroporous structures possess both large planar π-conjugated structures and macroporous structures, with -NH2 end groups, and their structural formulas are as follows:

[0015]

[0016] In the formula, the wavy line represents the topological structure of the extended molecule.

[0017] As a preferred technical solution:

[0018] The preparation method of the graphene wet spinning solution described above, and the preparation method of the two-dimensional conjugated material with macroporous structure are as follows: 1,3,5-triaminobenzene and pyromellitic tricarboxaldehyde in a molar ratio of 1.1-1.2:1 undergo a nucleophilic addition-elimination reaction to obtain the two-dimensional conjugated material with macroporous structure.

[0019] The preparation method of the graphene wet spinning solution described above involves the following steps for preparing a two-dimensional conjugated material with a macroporous structure: 1,3,5-triaminobenzene and trimesin are added to a solvent (dimethyl sulfoxide). Under nitrogen or inert gas protection, the mixture is heated to 140-150℃ and reacted for 20-24 hours. After post-treatment (the system is cooled to 50℃, acetone is slowly added while stirring vigorously; after the addition is complete, stirring is continued for 30 minutes, the mixture is allowed to stand and separate into layers, and the upper layer is discarded; acetone is added again to the lower precipitate for washing, stirring, allowing the mixture to stand and separate into layers, and discarding the liquid; this washing process is repeated twice, followed by filtration and drying at 60℃), the two-dimensional conjugated material with a macroporous structure is obtained.

[0020] The method for preparing a graphene wet spinning solution as described above includes the following steps:

[0021] (a) Under the condition of temperature T1 and simultaneous mechanical stirring and ultrasonic stirring, a second dispersion is added dropwise to the first dispersion, wherein the value of T1 is in the range of 40-50℃;

[0022] (b) After the addition is complete, stop ultrasonic stirring so that the two-dimensional conjugated material with macroporous structure can form a stable interaction with the graphene oxide sheet, and keep the reaction at a temperature for at least 2 hours;

[0023] (c) After cooling to a temperature of T2 so that the two-dimensional conjugated material with macroporous structure is precipitated and grown on the surface of graphene oxide sheet, stop mechanical stirring and let stand for at least 8 hours. The value of T2 is in the range of 0-4℃.

[0024] (d) After centrifuging the reaction system of step (c) at a temperature of T2, discard the supernatant and collect the lower centrifuged concentrate.

[0025] (e) Add washing liquid at temperature T2 to the lower centrifuged concentrate of step (d), centrifuge, and then discard the supernatant. Repeat this process once to obtain the graphene wet spinning solution.

[0026] In the above-described method for preparing a graphene wet spinning solution, in step (a), the mass ratio of the dispersed phase to the dispersion medium (which may be water, etc.) in the first dispersion is 1:40-60; the mass ratio of the dispersed phase to the dispersion medium (which may be methanol, ethanol, etc.) in the second dispersion is 1:20-40; and the volume ratio of the second dispersion to the first dispersion is 1:10-20.

[0027] In step (b), the heat preservation reaction time is 2-3 hours;

[0028] In step (c), the cooling rate is 3-5℃ / 10min, and the standing time is 8-12h;

[0029] In step (d), the centrifugation speed is 10000-12000 rpm and the time is 15-20 min;

[0030] In step (e), the washing solution is an aqueous solution of alcohol, and the volume ratio of alcohol to water in the aqueous solution of alcohol is 1:10. The solid content of the graphene wet spinning solution is 30-35%.

[0031] The present invention also provides a graphene wet spinning solution, which is prepared by the method described above for preparing a graphene wet spinning solution.

[0032] The present invention also provides a method for preparing graphene fibers, wherein graphene oxide fibers are obtained by wet spinning of a graphene wet spinning solution as described above, and then the graphene oxide fibers are reduced to obtain graphene fibers; wherein, the wet spinning includes a sizing process, and the sizing material contains a two-dimensional conjugated material with a macroporous structure as described above.

[0033] As a preferred technical solution:

[0034] The preparation method of graphene fiber described above, the wet spinning process is as follows: spinneret extrusion → coagulation bath coagulation → stretching → spray washing → drying → sizing → drying → winding.

[0035] The extrusion speed of the spinneret is 5-10 m / min;

[0036] The temperature of the coagulation bath is 4-8℃. The coagulation bath is a DMF aqueous solution of calcium chloride (calcium chloride mass fraction is 15-20%, and the volume ratio of DMF to water is 1:3-5), an aqueous solution of DMAc (DMAc to water volume ratio is 1:3-5), and an aqueous solution of NMMO (NMMO to water volume ratio is 1:3-5).

[0037] The stretch ratio is 1.3-1.5 times;

[0038] The slurry used for sizing has a mass concentration of 3-5% of a two-dimensional conjugated material with a macroporous structure, is in alcohol as the solvent, and is prepared at a temperature of 40-50℃.

[0039] The reduction process of the graphene fiber preparation method described above is as follows: immersing graphene oxide fibers in an aqueous solution of hydroiodic acid with a concentration of 1-5 mg / L, keeping the solution at 60-70℃ for 0.5-2 h, and then keeping the immersed graphene oxide fibers at 90-100℃ for 2-4 h.

[0040] This invention also provides a graphene fiber, prepared using the method described above; the graphene fiber has an electrical conductivity of 1672-1996 S / cm, a thermal conductivity of 643-789 W / (m•K), a flexural strength of 0.86-1.2 GPa, a flexural modulus of 56-78 GPa, and a flexural curvature of 0.24-0.33 mm. -1 .

[0041] This invention also provides a graphene fiber fabric, which is obtained by weaving or knitting a graphene fiber as described above; the graphene fiber fabric has a flexural fatigue life greater than 10. 8 Second, wear resistance life greater than 10 4 Second-rate.

[0042] Invention principle:

[0043] This invention uses graphene oxide as a raw material. On the one hand, its surface has a large number of epoxy functional groups and carboxyl groups, and the locations where these functional groups appear are also the defect sites of graphene oxide. These functional groups can serve as sites for modification reactions. On the other hand, it has better toughness than graphene, which is beneficial for spinning.

[0044] In the preparation of the wet spinning solution, this invention combines graphene oxide with a two-dimensional conjugated material with a macroporous structure (COF-NH2). Because COF-NH2 has a two-dimensional planar conjugated structure, it can form π-π interactions with the surface of graphene oxide through π electrons. The -NH2 groups at the ends of COF-NH2 can form ionic bonds with the carboxyl groups in graphene oxide, and the -NH2 groups at the ends of COF-NH2 can also form hydrogen bonds with the epoxy functional groups in graphene oxide. Therefore, graphene oxide and COF-NH2 undergo cross-layer self-assembly, with COF-NH2 appearing to lie flat between the graphene oxide sheets, which can achieve the following effects:

[0045] ① Improve the weavability of graphene fibers;

[0046] During the weaving process, graphene fibers inevitably undergo multiple bends. Because graphene is a two-dimensional material, graphene fibers possess extreme rigidity, low bending strength, and poor resistance to bending fatigue, making them generally unsuitable for weaving. For example... Figure 1 As shown, when the graphene fiber of the present invention is not subjected to external force, the two-dimensional conjugated material 2 with a macroporous structure is interspersed between the graphene oxide sheets 1 in a seemingly flat manner. When subjected to external force, the two-dimensional conjugated material 2 with a macroporous structure can play a sufficient buffering role by changing the arrangement direction and the shape of its planar cavity, preventing the graphene fiber from breaking under the action of external force. At the same time, this intramolecular mechanical buffering effect has sufficient resistance to bending fatigue strength, providing good weavability for the graphene fiber.

[0047] ② Improve the electrical and thermal conductivity of graphene fibers;

[0048] COF-NH2, which lies flat between graphene oxide sheets, improves the stacking order of graphene sheets in the graphene fiber, thus preserving the intrinsic properties of graphene. Therefore, the graphene fiber of this invention has high electrical and thermal conductivity. On the other hand, COF-NH2 has a large planar cavity structure, through which hydroiodic acid can pass during chemical reduction, facilitating its reach into the interior of the graphene oxide fiber and fully playing a role in chemical reduction. This improves the structural integrity of the graphene, allowing graphene fibers with high thermal and electrical conductivity to be obtained even without high-temperature reduction.

[0049] The present invention further improves the surface defects and roughness of graphene fibers by applying COF-NH2 to the surface of the shaped graphene oxide fibers, thereby significantly reducing the friction between the graphene fibers and preventing fiber breakage caused by friction between the fibers.

[0050] Beneficial effects:

[0051] The graphene fibers prepared by this invention possess high bending toughness and good electrical and thermal conductivity. Furthermore, their smooth surface causes no wear on loom needles during weaving and prevents breakage due to bending, thus meeting weaving requirements. In addition, the processing method for preparing graphene fibers according to this invention is also adaptable to the continuous production needs of graphene fibers and their fabrics. Attached Figure Description

[0052] Figure 1 In Figure a, COF-NH2 is a schematic diagram of the morphology of the graphene fiber prepared by the present invention before the application of bending stress during the bending stress process. In Figure b, COF-NH2 is a schematic diagram of the morphology of the graphene fiber prepared by the present invention after the application of bending stress during the bending stress process.

[0053] Figure 2 The infrared spectrum of the two-dimensional conjugated material with a macroporous structure prepared in Example 1 of this invention;

[0054] In the figure, 1-graphene oxide sheets, 2-two-dimensional conjugated material with macroporous structure. Detailed Implementation

[0055] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0056] To ensure that the performance of the substances used in each embodiment and comparative example is fully disclosed, the manufacturers and brands of the substances are specified. Other manufacturers and brands that conform to the limitations of this invention are also feasible.

[0057] The two-dimensional conjugated materials with macroporous structures prepared in the following embodiments have a large planar π-conjugated structure and a macroporous structure, and the end groups are -NH2, with the following structural formulas:

[0058] ;

[0059] In the formula, the wavy line represents the topological structure of the extended molecule.

[0060] The test methods for the relevant performance indicators in the following embodiments and comparative examples are as follows:

[0061] Electrical conductivity: The graphene fibers prepared in each embodiment and comparative example were used as samples. The samples were then laid flat on an insulating film, and both ends were fixed with conductive double-sided tape, ensuring that the sample and the contact section with the four probes were straight and without bending. In the fiber testing mode of the four-probe conductivity meter, the probes were pressed down to the sample surface, and a current of 10 μA was applied through the four-probe conductivity meter. The voltage value V and the resistance value R = V / I were then read. The conductivity of the sample was calculated based on the measured data. The calculation formula is: conductivity = 4l / (R·πd) 2 In the formula, l is the probe spacing (1.59 mm) and d is the diameter of the sample.

[0062] Thermal conductivity: The graphene fibers prepared in each example and each comparative example were used as samples, and the thermal conductivity of the samples was measured in accordance with the standard Q / 110000 BH 008-2018 "Test method for axial thermal conductivity of carbon fiber bundle".

[0063] Fiber bending strength, bending modulus, and bending curvature: The graphene fibers prepared in each example and comparative example were used as samples. First, according to GB / T 3362-2017 standard, 500 mm samples were wound onto a multifilament frame, then immersed in resin solution at 25°C (prepared according to A.3.3 of GB / T 3362-2017 standard) for 5 minutes, and then placed in an electric heating drying oven at 120°C for curing to obtain graphene fiber strips. The bending strength and bending modulus of the graphene fiber strips were then tested according to GB / T 1449-2005 "Test Method for Bending Properties of Fiber Reinforced Plastics". In the three-point bending test, the load-displacement curve was simultaneously recorded using a laser displacement sensor (Keyence LK-G5000, accuracy ±0.5μm) to obtain the maximum displacement δ (in mm) at the peak point of the curve. Then, the radius of curvature r was derived through geometric relationships. In the formula, L is the span of the spline. Then, the curvature κ is obtained according to the calculation formula, which is: .

[0064] Bending fatigue life: The graphene fiber fabrics prepared in each embodiment and comparative example were cut into standard sizes of 25mm × 50mm as samples, and then tested using a dynamic mechanical analyzer. The specific process was as follows: a three-point bending mode was adopted. First, the sample was placed horizontally between two fixed support points (span L = 40mm). Then, the maximum allowable bending angle of the sample was determined through pre-experiment, and the cyclic bending angle was determined to be 10°. The three-point bending stress was then calculated. Then, the displacement control mode was selected, and a vertically downward periodic load was applied at the center of the two fixed support points through a movable loading head (i.e., the loading head moves up and down in the form of a sine wave with a frequency of 1Hz). At the start of the test, the load-displacement curve was monitored in real time until the load decreased to the point of sample fracture. At the same time, the number of cycles from the initial loading to complete fracture was recorded, which is the bending fatigue life. The maximum allowable bending angle was determined by: quasi-static bending of the sample to fracture, obtaining δmax, setting δcyclic = 0.5 × δmax, and converting it to a bending angle θ = 10°. The formula for calculating the three-point bending stress is: three-point bending stress = 3FL / 2bh 2 In the formula, F is the loading load (N), which is given in real time by the testing software, L is the span, b is the sample width (i.e., 25 mm), and h is the sample thickness (in μm).

[0065] Example 1

[0066] A method for preparing a two-dimensional conjugated material with a macroporous structure, the specific process being as follows: 1,3,5-triaminobenzene and trimesin in a molar ratio of 1.1:1 are added to dimethyl sulfoxide, and the mixture is heated to 140℃ and reacted for 20 hours under nitrogen protection. After post-treatment, the two-dimensional conjugated material with a macroporous structure is obtained (its infrared spectrum is shown in Figure 1). Figure 2 (As shown).

[0067] A method for preparing a graphene wet spinning solution, the specific steps of which are as follows:

[0068] (a) Preparation of raw materials;

[0069] The first dispersion consists of graphene oxide (manufacturer: Beike Nanotechnology Co., Ltd., brand name: szbknm2010) and water in a mass ratio of 1:40.

[0070] The second dispersion consists of the two-dimensional conjugated material with macroporous structure prepared above and ethanol at a mass ratio of 1:20.

[0071] (b) Under the conditions of temperature T1 and simultaneous mechanical stirring and ultrasonic stirring, a second dispersion is added dropwise to the first dispersion at a rate of 2 drops / second; wherein T1 is 40°C, the volume ratio of the second dispersion to the first dispersion is 1:10, the mechanical stirring speed is 200 rpm, and the ultrasonic frequency is 5000 Hz.

[0072] (c) After the addition is complete, stop the ultrasonic stirring and keep the reaction at the temperature for 2 hours;

[0073] (d) Cool down to T2 at a rate of 3℃ / 10min, then stop mechanical stirring and let stand for 8 hours; where T2 is 0℃;

[0074] (e) After centrifuging the reaction system of step (d) at a temperature of T2, the supernatant is discarded and the lower centrifuged concentrate is collected; wherein, the centrifugation speed is 10000 rpm and the time is 15 min;

[0075] (f) Add an aqueous solution of ethanol at temperature T2 to the lower centrifuged concentrate of step (e), centrifuge, and then discard the supernatant. Repeat this process once to obtain the graphene wet spinning solution. The volume ratio of ethanol to water in the aqueous solution is 1:10, and the solid content of the graphene wet spinning solution is 30%.

[0076] A method for preparing graphene fibers, comprising the following steps:

[0077] S1. Preparation of raw materials;

[0078] Coagulation bath: DMF aqueous solution of calcium chloride, wherein the mass fraction of calcium chloride is 15% and the volume ratio of DMF (N,N-dimethylformamide) to water is 1:3;

[0079] Slurry: Composed of the two-dimensional conjugated material with macroporous structure obtained above and ethanol, wherein the mass concentration of the two-dimensional conjugated material with macroporous structure is 3%;

[0080] Hydroiodic acid aqueous solution: concentration 1 mg / L;

[0081] S2. The graphene wet spinning solution prepared above is subjected to wet spinning to obtain graphene oxide fiber; wherein, the wet spinning process is as follows: spinneret extrusion → coagulation bath coagulation → stretching → spray washing → drying → sizing → drying → winding.

[0082] The process parameters for wet spinning are as follows: the extrusion speed of the spinneret is 5 m / min; the temperature of the coagulation bath is 4℃; the draw ratio is 1.3 times; and the temperature of the sizing agent used for sizing is 40℃.

[0083] S3. Reduction treatment: Graphene oxide fibers are impregnated in hydroiodic acid aqueous solution and reacted at 60°C for 1 hour. Then, the impregnated graphene oxide fibers are reacted at 90°C for 2 hours to obtain graphene fibers.

[0084] The resulting graphene fibers had an electrical conductivity of 1672 S / cm, a thermal conductivity of 643 W / (m•K), a flexural strength of 1.2 GPa, a flexural modulus of 76 GPa, and a flexural curvature of 0.33 mm. -1 .

[0085] A method for preparing graphene fiber fabric, the specific process of which is as follows: graphene fiber fabric is obtained by weaving the above-mentioned graphene fiber; wherein the warp density is 120 threads / 10cm, the weft density is 150 threads / 10cm, and the basis weight is 40g / m². 2 .

[0086] The obtained graphene fiber fabric exhibits a flexural fatigue life of 1.33 × 10⁻⁶. 8 The wear life is 1.41 × 10⁻⁶ times. 4 Second-rate.

[0087] Comparative Example 1

[0088] A method for preparing a graphene wet spinning solution is basically the same as in Example 1, except that the first dispersion and the second dispersion are directly mixed (the amount and mixing time are the same as in Example 1).

[0089] A method for preparing graphene fibers is basically the same as in Example 1, except that the graphene wet spinning solution used is the one prepared in this comparative example.

[0090] The resulting graphene fibers exhibited an electrical conductivity of 854 S / cm, a thermal conductivity of 342 W / (m•K), a flexural strength of 0.38 GPa, a flexural modulus of 16 GPa, and a flexural curvature of 0.11 mm. -1 .

[0091] A method for preparing graphene fiber fabric is basically the same as in Example 1, except that the graphene fiber used is the one prepared in this comparative example.

[0092] The obtained graphene fiber fabric exhibits a flexural fatigue life of 5.86 × 10⁻⁶. 3 Second-rate.

[0093] Comparing Comparative Example 1 and Example 1, it can be seen that the electrical and thermal conductivity of the graphene fibers prepared in this comparative example is significantly reduced, and the bending strength, bending modulus, and bending curvature are worse. The bending fatigue life of the graphene fiber fabric woven with it is greatly reduced. This is because direct mixing and addition will affect the dispersion uniformity between the graphene oxide sheets and the macroporous two-dimensional conjugated materials. During the molding process, the macroporous two-dimensional conjugated materials will be unevenly distributed in the graphene oxide sheets. This will not only affect the charge carrier transport and thus affect the overall electrical and thermal conductivity, but also generate stress concentration points under external force, which will affect the mechanical properties of the material, resulting in a significant reduction in bending strength and bending fatigue life.

[0094] Comparative Example 2

[0095] A method for preparing a graphene wet spinning solution is basically the same as in Example 1, except that the second dispersion used in steps (a)-(b) is replaced with an equal mass of ethanol.

[0096] A method for preparing graphene fibers is basically the same as in Example 1, except that the graphene wet spinning solution used is the one prepared in this comparative example.

[0097] The resulting graphene fibers exhibited an electrical conductivity of 833 S / cm, a thermal conductivity of 325 W / (m•K), a flexural strength of 0.53 GPa, a flexural modulus of 38 GPa, and a flexural curvature of 0.15 mm. -1 .

[0098] A method for preparing graphene fiber fabric is basically the same as in Example 1, except that the graphene fiber used is the one prepared in this comparative example.

[0099] The obtained graphene fiber fabric exhibits a flexural fatigue life of 4.6 × 10⁻⁶. 5 Second-rate.

[0100] Comparing Comparative Example 2 with Example 1, it can be seen that the electrical and thermal conductivity of the graphene fibers prepared in this comparative example is significantly reduced, and the bending strength, bending modulus, and bending curvature are worse. The bending fatigue life of the graphene fiber fabric woven with it is greatly reduced. This is because the replaced graphene oxide does not contain a macroporous two-dimensional conjugated material. During the oxidation-reduction process, the reduction inside the fiber is insufficient, which leads to a decrease in the electrical and thermal conductivity of the graphene fiber. At the same time, under external stress, due to the lack of the stress buffering effect of the macroporous two-dimensional conjugated material between the graphene sheets, stress concentration points are easily formed, and the stress is difficult to release, ultimately resulting in a significant reduction in bending strength and a decrease in bending fatigue life.

[0101] Comparative Example 3

[0102] A method for preparing graphene fibers is basically the same as in Example 1, except that the sizing material used during sizing does not contain two-dimensional conjugated materials with macroporous structures.

[0103] The resulting graphene fibers had an electrical conductivity of 1453 S / cm, a thermal conductivity of 532 W / (m•K), a flexural strength of 0.78 GPa, a flexural modulus of 53 GPa, and a flexural curvature of 0.23 mm. -1 .

[0104] A method for preparing graphene fiber fabric is basically the same as in Example 1, except that the graphene fiber used is the one prepared in this comparative example.

[0105] The obtained graphene fiber fabric exhibits a flexural fatigue life of 7.8 × 10⁻⁶. 5 The wear life is 1.52 × 10⁻⁶ times. 3 Second-rate.

[0106] Comparing Comparative Example 3 with Example 1, it can be seen that the graphene fibers prepared in this comparative example have reduced electrical and thermal conductivity, decreased bending strength, bending modulus, and bending curvature, and the wear resistance of the graphene fiber fabric woven from them is greatly reduced. This is because the graphene fibers without surface sizing treatment with macroporous two-dimensional conjugated materials have a high degree of surface defects, which affects the surface electrical and thermal conductivity, leading to a decrease in electrical and thermal conductivity. In addition, the high degree of surface defects makes it easier for microcracks to propagate when subjected to bending stress, thus also leading to a decrease in bending performance. Furthermore, the graphene fibers without surface sizing treatment with macroporous two-dimensional conjugated materials have a large degree of surface defects and roughness, which increases the friction between graphene fibers. Therefore, it is impossible to effectively reduce fiber breakage caused by inter-fiber friction, ultimately leading to a sharp decrease in wear resistance.

[0107] Example 2

[0108] A method for preparing a two-dimensional conjugated material with a macroporous structure is as follows: 1,3,5-triaminobenzene and pyromellitic aldehyde in a molar ratio of 1.15:1 are added to dimethyl sulfoxide, and the mixture is heated to 150°C and kept at that temperature for 22 hours under nitrogen protection. After post-treatment, the two-dimensional conjugated material with a macroporous structure is obtained.

[0109] A method for preparing a graphene wet spinning solution, the specific steps of which are as follows:

[0110] (a) Preparation of raw materials;

[0111] The first dispersion consists of graphene oxide (manufacturer: Beike Nanotechnology Co., Ltd., brand name: szbknm2010) and water in a mass ratio of 1:50.

[0112] The second dispersion consists of the two-dimensional conjugated material with a macroporous structure prepared above and methanol at a mass ratio of 1:30.

[0113] (b) Under the conditions of temperature T1 and simultaneous mechanical stirring and ultrasonic stirring, a second dispersion is added dropwise to the first dispersion at a rate of 2 drops / second; wherein T1 is 45°C, the volume ratio of the second dispersion to the first dispersion is 1:15, the mechanical stirring speed is 300 rpm, and the ultrasonic frequency is 5000 Hz.

[0114] (c) After the addition is complete, stop the ultrasonic stirring and keep the reaction at the temperature for 2.5 hours;

[0115] (d) Cool down to T2 at a rate of 4℃ / 10min, then stop mechanical stirring and let stand for 10h; where T2 is 2℃.

[0116] (e) After centrifuging the reaction system of step (d) at a temperature of T2, the supernatant is discarded and the lower centrifuged concentrate is collected; wherein, the centrifugation speed is 11000 rpm and the time is 18 min;

[0117] (f) Add an aqueous methanol solution at temperature T2 to the lower centrifuged concentrate of step (e), centrifuge, and then discard the supernatant. Repeat this process once to obtain the graphene wet spinning solution. The volume ratio of methanol to water in the aqueous methanol solution is 1:10, and the solid content of the graphene wet spinning solution is 32%.

[0118] A method for preparing graphene fibers, comprising the following steps:

[0119] S1. Preparation of raw materials;

[0120] Coagulation bath: an aqueous solution of DMAc (N,N-dimethylacetamide), wherein the volume ratio of DMAc to water is 1:5;

[0121] Slurry: Composed of the two-dimensional conjugated material with macroporous structure obtained above and ethanol, wherein the mass concentration of the two-dimensional conjugated material with macroporous structure is 4%;

[0122] Hydroiodic acid aqueous solution: concentration 3 mg / L;

[0123] S2. The graphene wet spinning solution prepared above is subjected to wet spinning to obtain graphene oxide fiber; wherein, the wet spinning process is as follows: spinneret extrusion → coagulation bath coagulation → stretching → spray washing → drying → sizing → drying → winding.

[0124] The process parameters for wet spinning are as follows: the extrusion speed of the spinneret is 8 m / min; the temperature of the coagulation bath is 6℃; the draw ratio is 1.4 times; and the temperature of the sizing agent used for sizing is 45℃.

[0125] S3. Reduction treatment: Graphene oxide fibers are immersed in hydroiodic acid aqueous solution and reacted at 65°C for 2 hours. Then, the immersed graphene oxide fibers are reacted at 95°C for 3 hours to obtain graphene fibers.

[0126] The resulting graphene fibers exhibited an electrical conductivity of 1745 S / cm, a thermal conductivity of 664 W / (m•K), a flexural strength of 1.15 GPa, a flexural modulus of 78 GPa, and a flexural curvature of 0.29 mm. -1 .

[0127] A method for preparing graphene fiber fabric, specifically comprising: knitting the aforementioned graphene fibers to obtain graphene fiber fabric; wherein the basis weight is 40 g / m². 2 .

[0128] The obtained graphene fiber fabric exhibits a flexural fatigue life of 1.12 × 10⁻⁶. 8 The wear life is 1.26 × 10⁻⁶ times. 4 Second-rate.

[0129] Example 3

[0130] A method for preparing a two-dimensional conjugated material with a macroporous structure is as follows: 1,3,5-triaminobenzene and pyromellitic tricarboxaldehyde in a molar ratio of 1.2:1 are added to dimethyl sulfoxide, and the mixture is heated to 145℃ and kept at that temperature for 24 hours under nitrogen protection. After post-treatment, the two-dimensional conjugated material with a macroporous structure is obtained.

[0131] A method for preparing a graphene wet spinning solution, the specific steps of which are as follows:

[0132] (a) Preparation of raw materials;

[0133] The first dispersion consists of graphene oxide (manufacturer: Beike Nanotechnology Co., Ltd., brand name: szbknm2010) and water in a mass ratio of 1:60.

[0134] The second dispersion consists of the two-dimensional conjugated material with macroporous structure prepared above and ethanol at a mass ratio of 1:40.

[0135] (b) Under the conditions of temperature T1 and simultaneous mechanical stirring and ultrasonic stirring, a second dispersion is added dropwise to the first dispersion at a rate of 2 drops / second; wherein T1 is 50°C, the volume ratio of the second dispersion to the first dispersion is 1:20, the mechanical stirring speed is 250 rpm, and the ultrasonic frequency is 5000 Hz.

[0136] (c) After the addition is complete, stop the ultrasonic stirring and keep the reaction at the temperature for 3 hours;

[0137] (d) Cool down to T2 at a rate of 5℃ / 10min, then stop mechanical stirring and let stand for 12h; where T2 is 4℃;

[0138] (e) After centrifuging the reaction system of step (d) at a temperature of T2, the supernatant is discarded and the lower centrifuged concentrate is collected; wherein, the centrifugation speed is 12000 rpm and the time is 20 min;

[0139] (f) Add an aqueous solution of ethanol at temperature T2 to the lower centrifuged concentrate of step (e), centrifuge, and then discard the supernatant. Repeat this process once to obtain the graphene wet spinning solution. The volume ratio of ethanol to water in the aqueous solution is 1:10, and the solid content of the graphene wet spinning solution is 35%.

[0140] A method for preparing graphene fibers, comprising the following steps:

[0141] S1. Preparation of raw materials;

[0142] Coagulation bath: an aqueous solution of NMMO (N-methylmorpholine oxide), wherein the volume ratio of NMMO to water is 1:5;

[0143] Slurry: Composed of the two-dimensional conjugated material with macroporous structure obtained above and ethanol, wherein the mass concentration of the two-dimensional conjugated material with macroporous structure is 5%;

[0144] Hydroiodic acid aqueous solution: concentration 5 mg / L;

[0145] S2. The graphene wet spinning solution prepared above is subjected to wet spinning to obtain graphene oxide fiber; wherein, the wet spinning process is as follows: spinneret extrusion → coagulation bath coagulation → stretching → spray washing → drying → sizing → drying → winding.

[0146] The process parameters for wet spinning are as follows: the spinneret extrusion speed is 10 m / min; the coagulation bath temperature is 8℃; the draw ratio is 1.5 times; and the temperature of the sizing agent used for sizing is 50℃.

[0147] S3. Reduction treatment: Graphene oxide fibers are impregnated in hydroiodic acid aqueous solution and reacted at 70°C for 0.5 hours. Then, the impregnated graphene oxide fibers are reacted at 100°C for 4 hours to obtain graphene fibers.

[0148] The resulting graphene fibers exhibited an electrical conductivity of 1996 S / cm, a thermal conductivity of 789 W / (m•K), a flexural strength of 0.86 GPa, a flexural modulus of 56 GPa, and a flexural curvature of 0.24 mm. -1 .

[0149] A method for preparing graphene fiber fabric, the specific process of which is as follows: graphene fiber fabric is obtained by weaving the above-mentioned graphene fiber; wherein the warp density is 120 threads / 10cm, the weft density is 150 threads / 10cm, and the basis weight is 40g / m². 2 .

[0150] The obtained graphene fiber fabric exhibits a flexural fatigue life of 1.25 × 10⁻⁶. 8 The wear life is 1.08 × 10⁻⁶ times. 4 Second-rate.

[0151] Example 4

[0152] A method for preparing a two-dimensional conjugated material with a macroporous structure is as follows: 1,3,5-triaminobenzene and pyromellitic tricarboxaldehyde in a molar ratio of 1.1:1 are added to dimethyl sulfoxide, and the mixture is heated to 140°C and kept at that temperature for 24 hours under nitrogen protection. After post-treatment, the two-dimensional conjugated material with a macroporous structure is obtained.

[0153] A method for preparing a graphene wet spinning solution, the specific steps of which are as follows:

[0154] (a) Preparation of raw materials;

[0155] The first dispersion consists of graphene oxide (manufacturer: Shanghai Xiangtian Nanomaterials Co., Ltd., brand name: XT-Go) and water in a mass ratio of 1:50.

[0156] The second dispersion consists of the two-dimensional conjugated material with macroporous structure prepared above and ethanol at a mass ratio of 1:35.

[0157] (b) Under the conditions of temperature T1 and simultaneous mechanical stirring and ultrasonic stirring, a second dispersion is added dropwise to the first dispersion at a rate of 2 drops / second; wherein T1 is 50°C, the volume ratio of the second dispersion to the first dispersion is 1:15, the mechanical stirring speed is 250 rpm, and the ultrasonic frequency is 5000 Hz.

[0158] (c) After the addition is complete, stop the ultrasonic stirring and keep the reaction at the temperature for 2.5 hours;

[0159] (d) Cool down to T2 at a rate of 3℃ / 10min, then stop mechanical stirring and let stand for 10h; where T2 is 3℃;

[0160] (e) After centrifuging the reaction system of step (d) at a temperature of T2, the supernatant is discarded and the lower centrifugation concentrate is collected; wherein, the centrifugation speed is 12000 rpm and the time is 18 min;

[0161] (f) Add an aqueous solution of ethanol at temperature T2 to the lower centrifuged concentrate of step (e), centrifuge, and then discard the supernatant. Repeat this process once to obtain the graphene wet spinning solution. The volume ratio of ethanol to water in the aqueous solution is 1:10, and the solid content of the graphene wet spinning solution is 35%.

[0162] A method for preparing graphene fibers, comprising the following steps:

[0163] S1. Preparation of raw materials;

[0164] Coagulation bath: An aqueous solution of DMAc, wherein the volume ratio of DMAc to water is 1:3;

[0165] Slurry: Composed of the two-dimensional conjugated material with macroporous structure obtained above and ethanol, wherein the mass concentration of the two-dimensional conjugated material with macroporous structure is 4.5%;

[0166] Hydroiodic acid aqueous solution: concentration 3 mg / L;

[0167] S2. The graphene wet spinning solution prepared above is subjected to wet spinning to obtain graphene oxide fiber; wherein, the wet spinning process is as follows: spinneret extrusion → coagulation bath coagulation → stretching → spray washing → drying → sizing → drying → winding.

[0168] The process parameters for wet spinning are as follows: the extrusion speed of the spinneret is 6.5 m / min; the temperature of the coagulation bath is 5.5℃; the draw ratio is 1.4 times; and the temperature of the sizing agent used for sizing is 45℃.

[0169] S3. Reduction treatment: Graphene oxide fibers are impregnated in hydroiodic acid aqueous solution and reacted at 68°C for 0.5 h. Then, the impregnated graphene oxide fibers are reacted at 100°C for 3.5 h to obtain graphene fibers.

[0170] The resulting graphene fibers exhibited an electrical conductivity of 1869 S / cm, a thermal conductivity of 708 W / (m•K), a flexural strength of 1.08 GPa, a flexural modulus of 63 GPa, and a flexural curvature of 0.28 mm. -1 .

[0171] A method for preparing graphene fiber fabric, specifically comprising: knitting the aforementioned graphene fibers to obtain graphene fiber fabric; wherein the basis weight is 40 g / m². 2 .

[0172] The obtained graphene fiber fabric exhibits a flexural fatigue life of 1.17 × 10⁻⁶. 8 The wear life is 1.17 × 10⁻⁶ times. 4 Second-rate.

[0173] Example 5

[0174] A method for preparing a two-dimensional conjugated material with a macroporous structure is as follows: 1,3,5-triaminobenzene and pyromellitic tricarboxaldehyde in a molar ratio of 1.15:1 are added to dimethyl sulfoxide, and the mixture is heated to 150°C and kept at that temperature for 24 hours under nitrogen protection. After post-treatment, the two-dimensional conjugated material with a macroporous structure is obtained.

[0175] A method for preparing a graphene wet spinning solution, the specific steps of which are as follows:

[0176] (a) Preparation of raw materials;

[0177] The first dispersion consists of graphene oxide (manufacturer: Xianfeng Nanomaterials Technology Co., Ltd., brand name: XFSG01) and water in a mass ratio of 1:50.

[0178] The second dispersion consists of the two-dimensional conjugated material with macroporous structure prepared above and ethanol at a mass ratio of 1:40.

[0179] (b) Under the conditions of temperature T1 and simultaneous mechanical stirring and ultrasonic stirring, a second dispersion is added dropwise to the first dispersion at a rate of 2 drops / second; wherein T1 is 45°C, the volume ratio of the second dispersion to the first dispersion is 1:18, the mechanical stirring speed is 300 rpm, and the ultrasonic frequency is 5000 Hz.

[0180] (c) After the addition is complete, stop the ultrasonic stirring and keep the reaction at the temperature for 3 hours;

[0181] (d) Cool down to T2 at a rate of 5℃ / 10min, then stop mechanical stirring and let stand for 12h; where T2 is 3℃;

[0182] (e) After centrifuging the reaction system of step (d) at a temperature of T2, the supernatant is discarded and the lower centrifuged concentrate is collected; wherein, the centrifugation speed is 12000 rpm and the time is 15 min;

[0183] (f) Add an aqueous solution of ethanol at temperature T2 to the lower centrifuged concentrate of step (e), centrifuge, and then discard the supernatant. Repeat this process once to obtain the graphene wet spinning solution. The volume ratio of ethanol to water in the aqueous solution is 1:10, and the solid content of the graphene wet spinning solution is 33%.

[0184] A method for preparing graphene fibers, comprising the following steps:

[0185] S1. Preparation of raw materials;

[0186] Coagulation bath: DMF aqueous solution of calcium chloride, wherein the mass fraction of calcium chloride is 15% and the volume ratio of DMF to water is 1:5;

[0187] Slurry: Composed of the two-dimensional conjugated material with macroporous structure obtained above and ethanol, wherein the mass concentration of the two-dimensional conjugated material with macroporous structure is 5%;

[0188] Hydroiodic acid aqueous solution: concentration 1 mg / L;

[0189] S2. The graphene wet spinning solution prepared above is subjected to wet spinning to obtain graphene oxide fiber; wherein, the wet spinning process is as follows: spinneret extrusion → coagulation bath coagulation → stretching → spray washing → drying → sizing → drying → winding.

[0190] The process parameters for wet spinning are as follows: the extrusion speed of the spinneret is 9 m / min; the temperature of the coagulation bath is 7℃; the draw ratio is 1.3 times; and the temperature of the sizing agent used for sizing is 40℃.

[0191] S3. Reduction treatment: Graphene oxide fibers are impregnated in hydroiodic acid aqueous solution and reacted at 62°C for 1.5 hours. Then, the impregnated graphene oxide fibers are reacted at 95°C for 2.5 hours to obtain graphene fibers.

[0192] The resulting graphene fibers exhibited an electrical conductivity of 1953 S / cm, a thermal conductivity of 762 W / (m•K), a flexural strength of 0.94 GPa, a flexural modulus of 68 GPa, and a flexural curvature of 0.26 mm. -1 .

[0193] A method for preparing graphene fiber fabric, the specific process of which is as follows: graphene fiber fabric is obtained by weaving the above-mentioned graphene fiber; wherein the warp density is 120 threads / 10cm, the weft density is 150 threads / 10cm, and the basis weight is 40g / m². 2 .

[0194] The obtained graphene fiber fabric exhibits a flexural fatigue life of 1.09 × 10⁻⁶. 8 The wear resistance life is 1.25 × 10⁻⁶ times. 4 Second-rate.

Claims

1. A method of preparing a graphene wet spinning solution, characterized by, The first dispersion liquid with graphene oxide as the dispersed phase is mixed with the second dispersion liquid with the two-dimensional conjugated material with a large pore structure as the dispersed phase, and then the two-dimensional conjugated material with a large pore structure is first controlled to form a stable interaction with the graphene oxide sheet, then the two-dimensional conjugated material with a large pore structure is controlled to precipitate and grow on the surface of the graphene oxide sheet, and then the unreacted raw materials are removed, thereby obtaining the graphene wet spinning liquid. The preparation method of the graphene wet spinning liquid comprises the following steps: (a) under the condition of temperature T1 and mechanical stirring and ultrasonic stirring, the second dispersion liquid with the two-dimensional conjugated material with a large pore structure as the dispersed phase is added dropwise into the first dispersion liquid with graphene oxide as the dispersed phase, wherein the value range of T1 is 40-50℃; The preparation process of the two-dimensional conjugated material with a large pore structure is as follows: 1,3,5-triaminobenzene and triformylphenyl are added to a solvent, under the protection of nitrogen or inert gas, the temperature is raised to 140-150℃ and the reaction is maintained for 20-24h, after the system is cooled to 50℃, acetone is slowly added and stirred vigorously; after the addition is completed, the stirring is continued for 30min, the liquid is separated by standing, and the upper layer liquid is poured out; the lower layer precipitate is washed with acetone again, stirred, separated by standing, poured out, and the washing is repeated for 2 times, then the product is filtered and dried at 60℃, thereby obtaining the two-dimensional conjugated material with a large pore structure; The two-dimensional conjugated material with a large pore structure has a large planar π conjugated structure and a large pore structure, and the end group is -NH2; (b) after the dropwise addition is completed, the ultrasonic stirring is stopped, and the reaction is maintained for at least 2h; (c) after the temperature is lowered to T2, the mechanical stirring is stopped, and the standing is maintained for at least 8h, wherein the value range of T2 is 0-4℃; (d) after the reaction system of step (c) is treated by centrifugation under the condition of temperature T2, the supernatant is poured out, and the lower layer centrifugal concentrated liquid is collected; (e) after the lower layer centrifugal concentrated liquid of step (d) is treated by centrifugation with the washing liquid at temperature T2, the supernatant is poured out, and the process is repeated once, thereby obtaining the graphene wet spinning liquid.

2. The method for preparing a graphene wet spinning solution according to claim 1, characterized in that, In step (a), in the first dispersion liquid, the mass ratio of the dispersed phase to the dispersion medium is 1:40-60; in the second dispersion liquid, the mass ratio of the dispersed phase to the dispersion medium is 1:20-40; and the volume ratio of the second dispersion liquid to the first dispersion liquid is 1:10-20; In step (b), the reaction time is 2-3h; In step (c), the cooling rate is 3-5℃ / 10min, and the standing time is 8-12h; In step (d), the centrifugal treatment speed is 10000-12000rpm, and the time is 15-20min; In step (e), the solid content of the graphene wet spinning liquid is 30-35%.

3. A graphene wet spinning solution, characterized by, A graphene wet spinning liquid is prepared by using the preparation method of the graphene wet spinning liquid according to any one of claims 1-2.

4. A method of producing a graphene fiber, characterized by, After the graphene wet spinning liquid according to claim 3 is subjected to wet spinning to obtain graphene oxide fiber, the graphene oxide fiber is subjected to reduction treatment, thereby obtaining graphene fiber; wherein the wet spinning comprises a sizing process, and the sizing uses sizing agent containing the two-dimensional conjugated material with a large pore structure.

5. The method of claim 4, wherein the graphene fiber is prepared by the steps of: The process flow of wet spinning is: spinneret extrusion→coagulation in coagulation bath→stretching→spray washing→drying→sizing→drying→winding; ​ The speed of spinneret extrusion is 5-10 m / min; The temperature of coagulation bath is 4-8 ℃, and the coagulation bath is calcium chloride DMF aqueous solution, DMAc aqueous solution or NMMO aqueous solution; The stretching multiple is 1.3-1.5 times; The mass concentration of two-dimensional conjugated material with large pore structure in the sizing sizing agent is 3-5%, the solvent is alcohol, and the temperature is 40-50 ℃.

6. The method of claim 4, wherein the graphene fiber is prepared by the steps of: The reduction treatment process is: the graphene oxide fiber is immersed in a hydroiodic acid aqueous solution with a concentration of 1-5 mg / L, and is incubated at 60-70 ℃ for 0.5-2 h, and then the immersed graphene oxide fiber is incubated at 90-100 ℃ for 2-4 h. ​ 7. A graphene fiber, characterized by, The graphene fiber is prepared by the method according to any one of claims 4-6; the graphene fiber has an electrical conductivity of 1672-1996 S / cm, a thermal conductivity of 643-789 W / (m·K), a bending strength of 0.86-1.2 GPa, a bending modulus of 56-78 GPa, and a bending curvature of 0.24-0.33 mm -1 .

8. A graphene fiber fabric, characterized by, The graphene fiber as claimed in claim 7 is made by weaving or knitting; the bending fatigue life of the graphene fiber fabric is greater than 10 8 times, and the wear-resistant life is greater than 10 4 times.

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